Having been in this business for something approaching two decades, Kansas City Chiefs head coach Romeo Crennel has a signature defensive scheme that has been called many things. It is called reactive. It’s called bend-but-don’t-break. It’s called technique-oriented. It’s been praised by supporters to be the ultimate team-approach to successful defense, utiliting the ability of all eleven defenders to elevate the play of all their teammates. It’s been criticized by detractors as being unaggressive, more concerned with preventing big plays than promoting big stops, playing on your heels instead of pinning your ears back.

The Two-Gap

However you term it, it truly is a unique defensive style that stands in stark contrast to almost the entirety of other NFL defensive schemes, and fewer have promoted it more successfully than Crennel.

His style is termed the “two-gap 3-4″ defense. At its base, that means you have three lineman with their hands in the dirt, typically two defensive ends that are big and strong enough to take on offensive tackles and tall enough to deter passes by the quarterback in the pocket (think of Tyson Jackson’s prototypical 6’4″, 296 lbs frame), and a humongous, bulky nose tackle that is built for getting low, absorbing punishment and administering immediate push against a hopelessly outsized center (think of Jerrell Powe’s prototypical 6’2″, 331 lbs frame). Then you have four linebackers: two passrushers on the edge (one who is a more one-dimensional pocket assaulter, and the other who is a swiss army knife of abilities), and two in the middle (one who is more of a line of scrimmage attacker, and the other who is more coverage-oriented). This earns Crennel’s defense the “3-4″ moniker, for those who didn’t already know.

But roughly half the teams in the NFL play with a 3-4 arrangment. It’s Crennel’s two-gap approach is what truly sets this defense apart from every other style in the NFL.

From the Bears’ cover 2, to the Eagle’s wide 9, to the Texans’ one-gap, to the Patriots’ hybrid, to countless other 4-3 and 3-4 teams, the name of the game is very simple for the defensive line: get upfield. The players might line-up at different points along the defensive line. They might be bigger (3-4 nose tackles), smaller (cover 2 passrushers), ends, tackles, or rushbackers. But they all want to disrupt the pocket and get upfield.

Not so with the two-gap.

Think of this as your typical offensive line:

(C Gap) RT (B Gap) RG (A Gap) C (A Gap) LG (B Gap) LT (C Gap)

This is a comprehensive listing of the “gaps” in an offensive line. The “A” gap is between the center and guard, the “B” gap is between the guard and tackle. Most defenses in the NFL tell their defensive lineman to shoot a gap, which would either penetrate the pocket or at least disrupt the offensive line’s blocking assignments. Some defenses give a defensive tackle the job of occupying blockers, or “two-gapping,” meaning they focus less on getting upfield, and focus more with minding two gaps and clogging the lanes, offensive lineman be damned.

This two-gap strategy asks every single one of its defensive lineman to do exactly that. It turns the traditional role of the defensive lineman from pocket invader to space occupying, gap eater. There’s a reason young bucks like Tyson Jackson and Dontari Poe take a long time to adjust to it, the techniques involved in this are completely different than the simple “get up and go” of more attack-oriented defensive lines. (By my count, only four other teams in the NFL share this defensive style: Ravens, Jets, Dolphins, and now the Colts.)

The complexity of all of this aside, there is one thing needed to make this work. One thing needed to turn this defensive style, unique as it is, into an offense-wrecking machine:

The defensive linemen must occupy offensive linemen.

It’s that simple. It’s the first domino for the entire scheme to make sense. If these defensive linemen can force offensive lineman to double-team them, it frees up the linebackers behind them and to their flanks to make plays. If Glenn Dorsey and Jackson play their roles properly, Tamba Hali and Justin Houston are battling tight ends and fullbacks en route to the QB, rather than massive, athletic offensive tackles. If Poe can demand maximum attention in the interior of the line, it allows Derrick Johnson to flow to the ball freely. It therefore cuts down on the amount of time secondaries have to cover receivers. It allows the safeties to clamp down open spaces faster. The key to it all is that the defensive linemen must absorb multiple offensive linemen every play.
The 2012 Preseason Chiefs Defensive Line

But it’s a delicate ecosystem. If the defensive linemen do not regularly command double- and triple-teams, then the defensive line is getting no penetration and the linebackers are battling far too much on every play. Passing lanes will be bigger, and running the ball gets easier. In other words, if the defensive line can’t work, nothing works.

That’s what the 2012 preseason is teaching us. And if the problems we’re experiencing here carry over to the regular season, it may spell either the failure of this defense in Kansas City, or even worse, it may suggest that this defense is officially too antiquated to exist anymore in the modern NFL.

But during the first preseason game hosting the Arizona Cardinals, this was not a problem. The Cardinals bought the just-now-gaining-traction notion that Dorsey and Jackson are formidable talents worthy of maximum attention, and saw our nose tackle lineup of Anthony Toribio (fairly big), Dontari Poe (huge), and Jerrell Powe (very large) and convinced themselves that double-teaming would be a necessity.

We slaughtered them. First-team, second-team, third-team. Our rushbackers racked up sacks by the quarter, the Cards couldn’t run the ball, it was glorious. It was the true example of (a.) how talented our defense is, and (b.) how this scheme can maximize teamwork to create as hostile an environment for offenses as there can be in this league.

The Rams, too, tried taking on our defensive linemen two-at-a-time for much of the first half of the Chiefs second preseason game in St. Louis. The result was a pretty fair degree of success; despite the box score, the Rams had to convert two fourth downs to score their two touchdowns. The few runs broken off by Steven Jackson were anomolies of unusually missed assignments. The base lineup of Jackson, Toribio, and Dorsey were again a bit too much for the Rams’ offensive front to handle.

The second half of the Rams game, however, is where everything took a turn.

With a second-team defensive line setup of Ropati Pitoitua, Poe, and Amon Gordon, the Rams offense decided to try an experiment: what if we just didn’t double team them at all, ever?

The results were disasterous and frustrating to watch. The Rams single-teamed all three defensive lineman for their time on the field, and constantly launched both of their guards into the Chiefs linebackers (who were already struggling to begin with). Disasterously, none of the three players, with the rare exception of Gordon, were able to free themselves from their blockers, rarely ever being able to clog anything, and runners were frequently breaking into the second level as linebackers struggled to come off their blocks.

The Rams didn’t even make a pretense of it. They understood our depth and speed on the outside, so they ran right down our throats for the first few drives, to the visible frustration of players like Poe.

In the passing game, again, none of the linemen were double-teamed. All rushbackers were snagged by tackles before they could ever get into a serious move, and blitzers were easily absorbed by whomever the Rams kept in the backfield. By stymying our linemen with one blocker, the Rams opened everything up — and shut us down.

The Seahawks, perhaps noticing this on tape, decided that they’d repeat the same formula, this time against our starters, with consistently positive results. The Seahawks simply took the risk, figuring they had no shot if they had to double-team our 1′s. They figured it would be better to gamble on the chance the defensive line would disrupt them in one-on-one’s, while banking on the fact that they probably wouldn’t.

There were a few instances in short yardage where the offensive line felt the need to double players like Dontari Poe, and virtually every time the Chiefs made them pay. But for the vast majority of the first half, the Seahawks simply ignored double-teaming, which freed up LT Russell Okung to snag Hali on the edge, and allowed the guards to assault our linebackers and safeties in the run game.

There lies a fundamental flaw here: teams are starting to simply refuse doubling our defensive linemen. If that happens, neither of our starting ends (Dorsey and Jackson) have proven able to disengage and punish offenses for their lack of respect. Toribio’s ability to demand double teams has weakened considerably in light of his injury, and Dontari Poe still has miles to go before he can harness that ability.

Only third string NT Jerrell Powe has really shown the power and burst necessary to command double teams, but if teams think their best shot is just going one-on-one with everybody, it almost doesn’t matter who you put out there. Teams will continue to gamble that your linemen won’t adjust, and the entire defense will risk exposure as a result.

Is the problem with our players? Is it with the scheme? That answer is not yet clear.

What is clear is that this has been a Jekyll and Hyde defense all preseason, and it’s likely to stay that way if Romeo Crennel can’t force offenses to respect his defensive line.

I saw that wall-o-text and the immediate launch into x's and o's and figured I'd never make it through more than a couple paragraphs because I'm completely ADD. But this is well-written. I don't know that I agree 100% but I'll definitely take note tonight.

That article was written by someone that really doesn't understand the defensive scheme or offensive blocking assignments, but the basic premise is roughly accurate. Moreso that style of 3-4 could be considered somewhat outdated, and not so much because we have bad talent. It's a conservative defense that doesn't beat itself, but but its design really isn't set up to wreck opposing offenses either.

That article was written by someone that really doesn't understand the defensive scheme or offensive blocking assignments, but the basic premise is roughly accurate. Moreso that style of 3-4 could be considered somewhat outdated, and not so much because we have bad talent. It's a conservative defense that doesn't beat itself, but but its design really isn't set up to wreck opposing offenses either.

Well for one their are a lot more variabilities in what the down lineman do than he went into. It helps to better understand offensive blocking assignments. You'll rarely if ever see all 3 down lineman in a 3-4 getting double teamed on any given running play.

Just because a defensive lineman is getting double teamed doesn't make him a bad-ass in the offenses eyes, and just because he's being single blocked doesn't mean he's a wuss.

It's just the way offensive blocking schemes are drawn up.

A defensive lineman at the point of attack will generally draw a double team whether he's any good or not - particularly if they line up anywhere inside the tackles. Generally they'll be a double team at the point of attack, then one of the o lineman will slide to the linebacker. Good linebackers negate this by running thru the hole before the O-lineman can slide off and block them. Steeler linebackers always put on a clinic on this. They get in the backfield before the O lineman can get on them. The Chiefs O-line under Vermeil was GREAT at sliding off point of attack blocks and getting to the linebackers.

I doubt if the tidbit on the seahawks blocking strategy had anything to do with the chiefs defense, or their personnel, but was just the way their blocking assignments were drawn up based on the look the chiefs front showed based on alignment. When he was in Denver McDouche would often start games doing odd things with his o lineman on running plays to confuse a defense and get some easy yards, but generally speaking the assignments for any given play don't change from opponent to opponent near as much as what a lot of people think.

If it were stated "At it's worst, the defensive linemen must occupy offensive linemen" then I'd let it go.

"If Glenn Dorsey and Jackson play their roles properly, Tamba Hali and Justin Houston are battling tight ends and fullbacks en route to the QB, rather than massive, athletic offensive tackles"

If this were all that was required of the DL and the Chiefs rushed 2 OLB's from that, it'd mean this defense has a 5 man pass rush, which is just plain bullshit.

This is a defense with a 3 man line. A 3 man defensive line. Get that, folks. Keep it.

During run plays, these linemen are required to stop then run by clogging gaps, and if they get double teamed, they are still supposed to get off the block and make the play. During pass situations these DL make pressure and sack the QB. See Leonard Marshall, RDE/NYG and R Seymour, RDE/Pats. Hell, look up the stats on all those DL and you will see they could get after the QB.

If you have good players that can handle these positions, you will see any one of these linemen move up field and make the play behind the LOS, a tackle for a loss.

The only difference in this style is that your DL is expected to do with 3 men what other teams do with 4. Really, it is that simple from the front of the defense. Of course, we rarely see a DL in this defense that is a known pass rusher because it takes a real special player for this to happen. Like this guy;

8th year player Leonard Marshall, RDE and sack maniac in this defense. ALL 3 DL collapse the pocket forcing Montana to scramble. ROLB Lawrence Taylor was lined up LOLB during this play and he releases TE Brent Jones while playing the QB scramble, but the pressure came straight up the middle from those 3 DL.

This is not a sub package but the base 34 NYG defense -- the exact same defense the Chiefs currently run.

Your ROLB is your blitzer. He rushes the pass play and will also fall back in pass coverage. It just depends on the game situation. During this NYG play, LT was assigned the QB spy. He waited for Joe to make his move and then he made his move toward Montana, but whiffed and Marshall caught Montana from behind. But note where Marshall came from -- he was 5 yards deep into the backfield when he fell down and got back up to make this tackle.

You need the right players for this defense. Then it works real well. Until then, the excuses for this DL will continue. They are excuses, not strategies like this guy suggests.

I think it's funny when fans think they know defensive player responsibility on every down. Heck, they don't even always know what their responsibility is at times (see blown coverage in Seattle last week).

“Back when we drafted him, I mentioned that he might have more of an impact as a third-down player than a first- and second-down player because the techniques that we use on first and second are so different than what he has been used to,’’ coach Romeo Crennel said. “On third down, they’re more like what he was doing in college. He showed some flashes that he could do some things, particularly in the one-on-one situation, so that’s why we put him there in that pass-rush area.’’

That was Crennel's statement yesterday. From his statement, KC DL might not two gap on known passing downs.

You can't define Romeo's system as easily is this guy tries to. I understand it a little bit but, it's not black and white. In the last couple of games we continually rushed 5. The three down linemen and the two OLBs. We were trying to get one on one match ups all game. Again, it was very vanilla and Romeo was trying to do this.

In the first game against Arizona, we showed some things. We blitzed the MLBs and the safeties quite a bit. Other than that, we ran a different blitz maybe twice a game against Seattle and St. Louis.

Here's the basis of his defense in a nutshell. On running plays, you want the d-linemen to take up two guys, shed tackles, and make the stop. Mostly, you want them to take two so the MLB or safeties can make the tackle. The OLBs either come around the back to make the tackle or they stay put.

On Passing downs, their job is to make sure the OLB gets one vs. one blocking. That might mean taking two blockers and it might mean taking one. If we call a play that where the MLBs, safties, or corners blitz, the d-linemen's goal is to occupy as many blockers as possible so that they may run freely at the QB.

This guy is wrong. No one has figured jack shit out. We just aren't showing anything and the coaches are making it tough on our players.